Carp is a freshwater fish found all over the world, including in many nations where it has been introduced to provide food or sport. Carp are also domesticated and carefully bred as koi, an ornamental fish which originates in Japan. The nations of the world have different views on carp, with some countries viewing the fish as an invasive pest, while others find it pleasurable to fish for and consume.

In the wild, carp are not very distinguished looking fish, usually appearing in dark greens and browns. They are characterized by two small whiskers or barbels which hang in front of their faces, which include a low slung mouth and eye. Carp also have long dorsal fins, split tails, and several fins along their lower bodies which are small and evenly spaced. Carp are somewhat plump, and resemble oversized goldfish. Carp have been known to reach the outstanding weight of 80 pounds (36 kilos) in Europe, where the fish is highly prized for sport.

In the United States, most regions view the carp as the pest. Carp are omnivorous, and will devour everything small enough to be consumed in a waterway while muddying the water and tearing up aquatic plants. As a result, native fish species find the area uninhabitable and will migrate or, in some cases, die off. As a result, many states are trying to eliminate carp from their waterways to allow native species to flourish.

Carp were originally imported into the United States as food fish, and although they are not eaten in North America, the fish are popular for consumption in other parts of the world. Carp is a bony fish, and requires careful filleting or preservation. However, the flesh is white, firm, and somewhat sweet, depending on the environment the fish has been raised in. The meat of carp is very sensitive to environmental factors, and will change depending on what type of food the fish has eaten and what sort of contaminants it has been exposed to. Much of the carp in the United States has accumulated pollution and is therefore unsafe for human consumption.

In Japan, brightly colored carp are greatly prized as koi, and have been bred for centuries. Koi often appear in lakes and ornamental water bodies, and are often highly tamed. Many koi will take food from the hand, or come up to the surface of the water to look at people. Koi are divided into a number of categories, depending upon coloration, and many sell for substantial sums of money.

In Europe, the carp is viewed as a sport fish, and also eaten. Carp are relatively strong, especially when allowed to grow to large sizes, and many anglers pursue the fish in the lakes of Europe, especially in Eastern European nations.